vRayFur doesn't obey Light Linking

[MartinB]

Just stumbled upon this bug. It seems vRayFur doesn't obey light linking. Can't seem to upload the maya test scene I made but the images below should show the problem.

Two spheres with basic vrayFur applied, one strong key light coming down from above and a weak fill from the front. The bottom image has had the top down key light linked only to the right hairy sphere and blank sphere, but the left hairy sphere is still receiving illumination from it.

Testing with 2.20.01 official release and 2.25.01 nightlies up until one from a few days ago which is the last we have installed.

cheers
Martin

[t.petrov]

Hi Martin,

I confirm this problem and I've logged it as an issue in our tracker, so we won't forget about it.
Watch the change logs in the nightly builds to see when this feature is implemented.

Is this issue an urgent one?

/Teodor

[MartinB]

Its pretty urgent, we've just started lighting a commercial that has several characters covered in vrayFur. They were only tested in isolation but now they're in the same scene together a lighter flagged the problem.

We'll proceed as if we don't have light linking and the lighters will have to be careful where they place lights, but if a fix could be done in the next week that would be a amazing. (There's only just over two weeks left for lighting)

Cheers
Martin

[t.petrov]

Hi,

I've done some investigations and it seems it is impossible to do light linking with custom shape nodes. This is logged Maya bug (MAYA-7995).
So if you want this to be implemented correctly in Maya, you should bug them, so they can increase the priority of this particular bug.

Currently we can do two things:
1. We easily make the fur to use the same light linking as the one applied to the mesh the fur is attached to.
2. We will provide a way to modify the light linking in the post translate python callback, but this currently doesn't work and I don't know if it can be implemented fast/easy.

Is 1 a viable solution for your project at the moment? If it is I can add it pretty easily.

Best regards,
Teodor

[MartinB]

Option 1 would be great and would work perfectly for this project (the objects that have vrayFur applied are hidden by the fur covering so it won't be an issue for bits of skin etc that could show through)

Thanks for looking into the Teodor!

[t.petrov]

Ok,

Variant 1 should be implemented in the next nightly build (the revision should be >= 20062).
Please test it and report if there are any problems with it.

/Teodor

[MartinB]

Cheers, I'll keep an eye out for it and let you know how it goes.

Thanks again for such a fast response!

[MartinB]

Just installed build 20069 and light linking seems to be working correctly now

Thanks for such a fast fix!